In addition to normal speech and data connections set up on traffic channels in digital mobile communication systems, short digital data messages, short messages, transferred on the control and signalling channels of the systems, may be sent amid actual signalling. A short message service centre is added in association with the mobile communication system for relaying short messages. In connection with a mobile originated short message, a subscriber creates the short message by means of the keyboard of a terminal, and the terminal submits the short message on a signalling channel via a base station and a mobile switching centre to the short message service centre. The short message service centre forwards the short message to another network, or on signalling channels via the mobile communication network to the terminal of another subscriber.
Services offered to subscribers via short messages also increase constantly. Several in e.g. voice and text mode delivered services may be offered to subscribers along with short messages. In addition to normal mobile terminating (MT) and mobile originated (MO) short messages, a subscriber may receive e.g. notices, ads, personal reminders, and may order information on sources offering these to his/her mobile station, and may transfer measuring results from one location to another, etc.
As the supply increases, an advantageous way to deal with the services is to arrange different kind of services to different short message service centres. By this time some implemented networks comprise several short message service centres, and as the selection of services increases, the number of short message service centres in a network will continue to grow. A number of short message service centres may be linked to a mobile communication network, e.g. one dealing with operations related to short messages and speech mail between mobile stations, another with telefax and e-mail operations, and a third with operations related to information services offered (e.g. weather report, stock exchange rates, sports results etc.).
Currently the addition of short message service centres to the network causes a subscriber extra work in connection with their use, because in order to be able to direct a message to the desired short message service centre, the user has to know and remember the addresses of available short message service centres and update the number of the short message service centre used by the mobile station so that it corresponds to the desired destination of the message. In practice, such activity is not required of a subscriber, but instead the services have to be offered in an as user friendly form as possible in order to be able to produce services profitably to an adequately large number of subscribers.